Briggs Softworks

It just happens randomly. Sometimes callbacks are working for a few days, but after updating to 4.43 they stopped 2 times already. Error Log shows nothing, server is working properly, everything else is functioning, but the callbacks just stop sending data to the PHP script and the servers needs to be restarted.

I'm not sure if this is the problem caused by the software or it might be caused by something else. However, nothing else is running on that VM

The only change in 4.43 regarding callbacks is the addition of the SessionID parameter to the Login callback. The callback system has its own worker thread and that wasn't changed. Any kind of failure in making the call should result in an entry in the error log. Which callback events do you have enabled?

Only Balance and Hand events. It seems it is just a coincidence that it started behaving like this with the update. I already mentioned, that it stopped working many times before the update, so it's not specifically something wrong on this update. I have seen some errors with the callback, I googled about it and it said something about Timeout. However - one timeout shouldn't be the reason to stop sending data at all. Also, it did not actually match with the time when it stopped working that day.

Setting enable to off and then back on again will cause the HTTP component to free and recreate itself again without needing to stop the server. Have you tried that? It can be done manually in the Windows console or via the SystemSet command in the API. You should then get an event log entry showing "Callback socket reset".